Buddhist philosophy is the branch of Eastern philosophy based on the teachings of Gautama Buddha (c. 563 BCE- c. 483 BCE). Buddhist philosophy deals extensively with problems in metaphysics, phenomenology, ethics, and epistemology.

From its inception, Buddhism has had a strong philosophical component. Buddhism is founded on the rejection of certain orthodox philosophical concepts, in which the Buddha had been instructed by various teachers. Buddhism rejects atheism, theism, monism, and dualism alike. The Buddha criticized all concepts of metaphysical being and non-being, and this critique is inextricable from the founding of Buddhism.Particular points of Buddhist philosophizing have often been the subject of disputes between different schools of Buddhism. Metaphysical questions such as "Is there a god?" and "Does the soul (Atman) really exist?" have divided the Buddha's followers even during his own lifetime, and epistemological debates over the proper modes of evidence have always been lively in Buddhism.Readers should note that theory for its own sake is not valued in Buddhism, but theory pursued in the interest of enlightenment for oneself or others is fully consistent with Buddhist values and ethics.

Some have asserted that Buddhism as a whole is a philosophy rather than a religion. Proponents of such a view may argue that (a) Buddhism is non-theistic (i.e., it has no special use for the existence or nonexistence of a god or gods) or atheistic and (b) religions necessarily involve some form of theism. Others might contest either part of such an argument. Other arguments for Buddhism "as" philosophy may claim that Buddhism does not have doctrines in the same sense as other religions; the Buddha himself taught that a person should accept a teaching only if one's own experience verifies it.Arguments against Buddhism as a philosophy might call attention to the way Buddhism's pervasive inclusion of supernatural entities (not "gods" in the sense of Western monotheism, of course), to what most scholars identify as worship practices (ceremonial reverence of saints, etc.), to Buddhism's thoroughly developed hierarchies of clergy (not usually characteristic of a "philosophy"), and its overall religious organization.A third perspective might take the position that Buddhism can be practiced either as a religion or as a philosophy. A similar distinction is often made with reference to Taoism.

Lama Anagorika Govinda expressed it as follows in the book 'A Living Buddhism for the West':

"Thus we could say that the Buddha's Dharma is,as experience and as a way to practical realization, a religion;as the intellectual formulation of this experience, a philosophy;and as a result of self-observation and analysis, a psychology.Whoever treads this path acquires a norm of behavior that is not dictated from without, but is the result of an inner process of maturation and that we - regarding it from without - can call morality."

It should also be noted that in the South and East Asian cultures in which Buddhism achieved most of its development, the distinction between philosophy and religion is somewhat unclear and possibly quite spurious, so this may be a semantic problem arising in the West alone.

Decisive in distinguishing Buddhism from what is commonly called Hinduism is the issue of epistemological justification. The schools of Indian logic recognize a certain set of valid justifications for knowledge, while Buddhism recognizes a smaller set. Both accept perception and argument, for example, but for the orthodox schools (of Hinduism), the received textual tradition (e.g., the Vedas) is in itself an epistemological category equal to perception and argument (although this is not necessarily true for some of the non-orthodox schools, like Vedanta). Thus, in the orthodox schools, if a claim was made that could not be substantiated by appeal to the textual canon, it would be viewed as ridiculous as a claim that the sky was green.

Buddhism, on the other hand, rejected an inflexible reverence of accepted doctrine. As the Buddha said:

Do not accept anything by mere tradition. . . Do not accept anything just because it accords with your scriptures. . . Do not accept anything merely because it agrees with your pre-conceived notions. . . But when you know for yourselves -- these things are moral, these things are blameless, these things are praised by the wise, these things, when performed and undertaken, conduce to well-being and happiness -- then do you live acting accordingly.-the Kalama Sutta, Anguttara Nikaya III.65

In earliest Buddhism and today still in Theravāda and the Madhyamaka, any metaphysical essence or being underlying the play of phenomenal experience is rejected. No "soul" or permanent self was recognized, and the perception of a continuous identity was held to be an illusion.

Any feeling whatsoever, any perception whatsoever, any mental processes whatsoever, any consciousness whatsoever -- past, future, or present; internal or external; blatant or subtle, common or sublime, far or near; every consciousness -- is to be seen as it actually is with right discernment as "This is not mine. This is not my self. This is not what I am."-the Anattalakkhana Sutta, Samyutta Nikaya XXII.59

From within the context of the Madhyamaka, we find Candrakirti:

"Self is an essence of things that does not depend on others; it is an intrinsic nature. The non-existence of that is selflessness".-Bodhisattvayogacaryācatuḥśatakaṭikā (Bodhisattvayogacaryacatuhsatakatika) 256.1.7

This anti-essentialist teaching, known as anatta, brought up many questions. If there is no ātman or Brahman underlying the objects and events of the universe, how could they be explained? What gave them their existence? And if there was no "self", who makes the decisions we think we make, and what gets reincarnated?Early Buddhist philosophers and exegetes created a pluralist metaphysical and phenomenological system in which all experiences of people, things, and events, can be broken down into smaller and smaller perceptual or perceptual-ontological units called dharmas. These dharmas (roughly synonymous with "phenomena") were interpreted differently by different schools: some held they were real, some held only some were real, some held all were illusory, some held they were empty, some held they were intrinsically associated with suffering, etc.Other debates in metaphysics and phenomenology include the issue of the Pudgala, or "person", which was inserted by the Pudgalavada school to replace the ātman as that which transmigrates and that which carries the burden of karma from one life to another. Other schools made unsurprising objection to this. There were further sub-debates regarding whether the pudgala was real or illusory or something in between. The Yogacara school, somewhat later, would later elevate the mind to act as a substitute for Brahman, much as the Pudgala replaces the ātman.In many or all of these debates, some would point out the irony of pursuing questions which the Buddha was often prone to refuse to answer, on the grounds that they were non-conducive to enlightenment.

The original positive Buddhist contribution to the field of metaphysics is pratītyasamutpāda, which arises from the Buddhist critique of Indian theories of causality. It states that events are not predetermined, nor are they random, and it rejects notions of direct causation owing to the need for such theories in the Indian context to be undergirded by a substantialist metaphysics. Instead, it posits the arising of events under certain conditions which are inextricable, such that the units in question at no time have independent existence.

This being, that becomes.From the arising of this, that arises.This not being, that does not become.From the ceasing of this, that ceases.-Samyutta Nikaya ii.28

Pratitya-samutpada goes on to posit that certain specific events, concepts, or realities are always dependent on other specific things. Craving, for example, is always dependent on, and caused by, emotion. Emotion is always dependent on contact with our surroundings. This chain of causation purports to show that the cessation of decay, death, and sorrow is indirectly dependent on the cessation of craving, and ultimately dependent on an all-encompassing stillness.Nāgārjuna, one of the most influential Buddhist philosophers, asserted a direct connection between, even identity of, dependent origination, anatta, and śūnyatā. He pointed out that implicit in the early Buddhist concept of dependent origination is the lack of any substantial being (anatta) underlying the participants in origination, so that they have no independent existence, a state identified as emptiness (śūnyatā), or emptiness of a nature or essence (sva-bhāva). This element of Nāgārjuna's thought is relatively uncontroversial, but it opens the way for his identification of saṃsāra and nirvana, which was revolutionary.

This doctrine comes from the Avatamsaka Sutra and its associated schools. It holds that all phenomena are intimately connected. Two images are used to convey this idea. The first is known as Indra's net. The net is set with jewels which have the extraordinary property that they reflect all of the other jewels. The second image is that of the world text. This image portrays the world as consisting of an enormous text which is as large as the universe itself. The 'words' of the text are composed of the phenomena that make up the world. However, every atom of the world contains the whole text within it. It is the work of a Buddha to let out the text so that beings can be liberated from suffering.This idea was enormously influential on the Japanese monk kūkai in founding the Shingon school of Buddhism.

Although there are many ethical tenets in Buddhism that differ depending on whether one is a monk or a layman, and depending on individual schools, the Buddhist system of ethics can always be summed up in the Eightfold Path.

And this, monks, is the noble truth of the way of practice leading to the cessation of suffering -- precisely this Noble Eightfold Path -- right view, right resolve, right speech, right action, right livelihood, right effort, right mindfulness, right concentration.-Samyutta Nikaya LVI.11

The purpose of living an ethical life is to escape the suffering inherent in (unenlightened) worldly life. Although early Buddhism (Hinayana) is contrasted with later Buddhism (Mahayana) in that the latter emphasizes striving for the enlightenment of all (apparent) beings rather than simply oneself, in neither case can the motivation for ethical living be called 'selfish', because Buddhist doctrine holds the notion of a 'self' to be illusory.Buddhist teachings claim that there is no real difference between ourselves and others; therefore one should attempt to increase the happiness of all living things as eagerly as one's own. This is why many Buddhists choose to be vegetarians.

The philosophical outlook of Earliest Buddhism was primarily negative, in the sense that it focused on what doctrines to reject more than on what doctrines to accept. This dimension has been preserved by the Madhyamaka school. It includes critical rejections of all views, which is a form of philosophy, but it is reluctant to posit its own. Only knowledge that is useful in achieving enlightenment is valued. The cycle of philosophical upheavals that in part drove the diversification of Buddhism into its many schools and sects only began once Buddhists began attempting to make explicit the implicit philosophy of the Buddha and the early Suttas.After the death of the Buddha, attempts were made to gather his teachings and transmit them in a commonly agreed form, first orally, then also in writing (The Tripitaka). In addition to collecting the Buddha's speeches and rules for monastic life (Vinaya), monks soon undertook to condense what they considered the essential elements of Buddhist doctrine into lists of categories, provided with extensive commentary. This process took shape from about the 2nd century BCE to probably the 2nd century CE.

Arthur Schopenhauer in his "World as Will and Idea" presented a description of suffering and its cause in a Western garb.

Baruch Spinoza, though he argued for the existence of a permanent reality, asserts that all phenomenal existence is transitory. In his opinion sorrow is conquered "by finding an object of knowledge which is not transient, not ephemeral, but is immutable, permanent, everlasting." Buddhism teaches that such a quest is bound to fail.

David Hume, after a relentless analysis of the mind, concluded that consciousness consists of fleeting mental states. Hume's Bundle theory is a very similar concept to anatta.